This invention relates to hand and foot operated swimming aids, and more particularly to a manually powered underwater paddle and a single vertical, feet attached fin, whose combined operations are enhanced by a swimmer's normal body motion.
Double bladed paddles are well known for propulsion of kayaks and canoes. They have a shaft to be held by two hands with a blade at each end of the shaft. The shaft is held at an angle to the horizontal with the propelling blade immersed and forced against the water while the returning blade is above water encountering no resistance. The blades are alternately immersed in this fashion so that there is a net forward thrust generated.
U.S. Pat. Nos. 5,114,371 issued May 19, 1992 to Alonzo and 3,510,894 issued Jan. 14, 1969 to Eriksen describe such paddles for swimmers. They feature a mid shaft float and operate at the water surface where the return blade may also be lifted out of the water.
U.S. Pat. 4,832,631 issued May 23, 1989 to Gag describes a double bladed paddling device for undersurface swimmer use in which a crank shaft connects the blades. It is operated with a rotary motion. The blades are pivotally mounted on the crank shaft and a special clutch mechanism fixes the driving paddle and releases the returning paddle so that it will rotate to a low resistance position on the shaft. The clutch mechanism is complex and vulnerable to the corrosive effects of immersion. The operating motion is not one which takes advantage of the major upper torso muscles of a swimmer.
U.S. Pat. No. 3,557,397 issued Jan. 26, 1971 to Margolies, and U.S. Pat. No. 4,857,024 issued Aug. 15, 1989 to Evans teach a swim fin to be mounted on an individual foot with a specially shaped, horizontal blade having special flexing responses that are greater when forced through water in a first direction than in a second direction so that greater resistance is offered on the power stroke of the kick, and less on the return stroke. These, and most foot attached devices have horizontal blades requiring an up and down leg motion for best effect.
However, normal alternate arm swimming strokes cause a side to side leg motion, not an up and down motion.
U.S. Pat. Nos. 4,541,810 issued Sep. 17, 1985 to Wenzel, 4,781,637 issued Nov. 1, 1988 to Caires, and 3,934,290 issued Jan. 27, 1976 to Le Vasseur all teach a blade in which both feet mount, but the blade is horizontal.
U.S. Pat. No. 3,987,509 issued Oct. 26, 1976 to Patterman teaches a pair of vertical blades, one on each foot, with each blade having a different shape and, in combination, presenting a fin like a fish's tail.
None of the prior art teach a two bladed paddle with flexible blade features for undirectional resistance for use in combination with an apparatus mounting on both feet having a flexible vertical blade for gaining special propulsive forces from the side to side motion of the feet generated by the alternating paddle strokes.